Step 7: Other stuff
1. Water Proofing - Cardboard falls apart fast when wet. Paint it with some kind of roofing paint or put a plastic laminate on the outside. Or use a material that is water proof (see materials below).
2. Doors and Windows - Use framing windows for RV's or just cut flaps in the sides. The obvious place for the door is in the overlapped wall section where the strength is greater.
3. Floor - Make the bottom floor flaps longer to get complete coverage. Or use something removable like a plastic sheet or Coroplast.
4. That Hole in the Top - The roof may be extended all the way to a point. The hole comes in handy for ventilation and lighting. Either way, the roof needs a cap at the top to keep the rain out. Use translucent material for natural lighting. Include a vent for ventilation.
5. Materials - Corrugated cardboard folds easily, but needs water proofing for outdoor use. Coroplast is an amazing material: water proof, inexpensive, light, and durable. You may need to cut away one layer of material to make creases that folds neatly. I use a Dremel with a cutting tool. Making wider cuts makes folding easier. Plywood or foam board may be used, with many advantages, but more tape is need to hinge everything together.
6. Number of Sides - 3 or more. 4 sides for the traditional square. The more sides, the rounder and more yurt-like the structure.
7. The bottom of the pleats in the roof must slope outward to drain water to the outside of the structure. If you change the design, do some calculations to make sure the pleat slope is correct, or build a model from paper to check the design.